In Focus's latest tribute to World War 2, called Daring Raids and Brutal Reprisals, is perhaps the most stomach-turning yet. Graphic content awaits, but this is war. You should know that already.

The comparatively tame image above depicts one of the 16 bombers that took part in the famous Doolittle Raid. While the raid was not considered successful in regards to damage caused to Japanese infrastructure, it was a smal psychological victory for the United States. Only months earlier the Japanese had had Pearl Harbor and American morale was low, and this raid proved effective at showing the people that Japan was not invincible.